Sorry to give offense, Manoj. I should have grepped the whole chapter
before wondering about "<unknown>", and I should have mentioned that I
really just use section 6.4 most of the time (because I *think* I
remember what each of the cases are for).
The fact that a non-version-number string literal with shell redirection
operators in it was a valid value of "old-version", "new-version",
"most-recently-configured-version", and so forth, did not occur to me.
I'd propose a Policy amendment dropping support for this long-obsolete
dpkg behavior, but I reckon I've lost my Policy-amendment-proposing
credentials in your eyes.
I do continue to think that:
if [ -n "$var" ]
is more readable than
if [ "${var+set}" = "set" ]
...but I remain open to being directed to a section of the Policy manual
that firmly establishes my wrongness on that front as well. :)
--
G. Branden Robinson | Men use thought only to justify
Debian GNU/Linux | their wrong doings, and speech only
branden@debian.org | to conceal their thoughts.
http://people.debian.org/~branden/ | -- Voltaire